What does it cost to call a frontier-grade LLM through its API in October 2026? The honest answer: between 10 per million input tokens depending on the model — a 100x spread inside a single provider's catalog, and wider across providers. This guide compares verified, dated prices so you can pick the cheapest model that actually solves your task.
**The cheapest usable frontier-grade API calls in October 2026 start at about 0.50–2 to $10.
Last verified: October 1, 2026. LLM prices fall monthly. Treat this table as a snapshot — every provider's own pricing page is the source of truth.
LLM API price comparison (October 2026)
Prices are list price per 1 million tokens (MTok), input/output, from each provider's published pricing:
| Model | Input $/MTok | Output $/MTok | Notes |
|---|---|---|---|
| OpenAI GPT-6 Luna | $0.10 | $0.50 | High-volume workhorse, 1M context |
| xAI Grok 4.1 Fast | $0.20 | ~$0.50–1.50 | Fast/cheap tier of the Grok family |
| Google Gemini Flash (promo) | $0.75 | $3.75 | Promotional paid-tier pricing through Dec 31, 2026 |
| DeepSeek V4 (open-weight MoE) | ~$0.50–1.00 | ~$1.50–2.00 | Historically the lowest-priced frontier-grade API; 1M context |
| Mistral Large 3 | $0.50 | $1.50 | European frontier at open-weight-adjacent pricing |
| Grok Build 0.1 | $1.00 | $2.00 | xAI's coding-tier model |
| Anthropic Claude Haiku 4.5 | ~$1 | ~$5 | Small-model tier with extended thinking |
| Anthropic Claude Opus 5.5 | ~$4 | ~$20 | Agentic coding leader, ~40% cheaper to run than Opus 5 |
| xAI Grok 4.7 | $2.00 | $6.00 | Flagship, 500K context |
| OpenAI GPT-6.1 Sol | $2 | $10 | Near-Astra performance |
| OpenAI GPT-6 Astra | $10 | $50 | Flagship reasoning/coding, 1.05M context |
Sources: OpenAI's model docs (GPT-6 family), xAI's API pricing page (Grok 4.7, Grok 4.1 Fast, Grok Build), Anthropic's Claude Opus 5.5 announcement, Mistral's pricing (Large 3), and Google's Gemini API pricing page (promotional window). DeepSeek's exact V4 figures move with its aggressive repricings — check platform.deepseek.com for the live number.
How to read this table
- The efficient frontier is real. GPT-6 Luna at 0.50 handles classification, extraction, summarization and most chat at roughly 1/100th of flagship cost. Paying flagship prices only makes sense for hard reasoning, long-horizon coding and agentic work.
- Output tokens dominate your bill. Output is consistently 3–5x input price. A model that rambles is a model that costs — reasoning tokens included. Cap max output in the Space's global params to keep budgets honest.
- Open-weight ≠ free hosting. DeepSeek V4 and Mistral's open weights are cheap via their official APIs, and if you host them yourself (Ollama, vLLM), the marginal token cost is your electricity.
- Promotional windows expire. Gemini's promo pricing and xAI's data-sharing credits run on clocks (Dec 31, 2026 for Gemini's window). Calendar them.
Three ways to pay less (without switching platforms)
- Route by task, not by loyalty. Use a cheap model for 80% of turns and escalate to a flagship when a task is hard. In SynthHires you switch the active model mid-conversation — the BYOK model means your keys work across the whole catalog.
- Stack free tiers behind your paid ones. Gemini, Groq, Cerebras, Cohere and OpenRouter's
:freeroster still cost $0 for light use — see our free API keys guide. - Use an aggregator for tail models. One OpenRouter key reaches 500+ models, so an experiment on an obscure cheap model doesn't mean a new vendor account.
FAQ
What is the cheapest LLM API in October 2026?
OpenAI's GPT-6 Luna is the cheapest verified frontier-grade API at 0.50 per million output tokens, with a 1M-token context window. DeepSeek's V4 family and Grok 4.1 Fast are close behind in the 1 range.
Is a cheaper model good enough for real work?
For chat, summarization, extraction, and routine code assistance — usually yes. For multi-step agentic workflows, hard reasoning, and large refactors, flagship models still measurably outperform. The practical strategy is routing: cheap models by default, flagship on demand.
How much does 1 million tokens actually cost me per month?
A heavy daily user generates roughly 10–30 million tokens per month. On a 0.50 model that's about 10/100–800/month. This is why task-routing matters more than chasing the absolute cheapest sticker price.
Do I pay the platform or the provider?
With SynthHires' BYOK architecture you always pay the provider directly — there is no token markup, no resold credits, no platform-side key vault. Your keys stay encrypted in your browser (AES-256-GCM). Read the BYOK architecture explainer for the mechanics.
Compare the models themselves, not just the prices: GPT-6 vs Claude Opus 5.5, or get every key in one place with the Get API keys guide.